Domain relationships

Description

Enzymes that participate in the transfer of one-carbon units require the coenzyme tetrahydrofolate (THF).
Various reactions generate one-carbon derivatives of THF, which can be interconverted between different
oxidation states by methylene-THF dehydrogenase (EC:1.5.1.5), methenyl-THF cyclohydrolase (EC:3.5.4.9)
and formyl-THF synthetase (EC:6.3.4.3) [PMID: 2541774, PMID: 8485162]. The dehydrogenase and cyclohydrolase
activities are expressed by a variety of multifunctional enzymes, including the tri-functional eukaryotic
C1-tetrahydrofolate synthase [PMID: 2541774]; a bifunctional eukaryotic mitochondrial protein; and the
bifunctional Escherichia coli folD protein [PMID: 2541774, PMID: 8485162]. Methylene-tetrahydrofolate dehydrogenase and
methenyltetrahydrofolate cyclo-hydrolase share an overlapping active site [PMID: 2541774], and as such are
usually located together in proteins, acting in tandem on the carbon-nitrogen bonds of substrates other
than peptide bonds.

This entry represents the NAD(P)-binding domain found in these enzymes.